The 35-year-old actor stopped by NBC's Late Night Wednesday, where he revealed to host Seth Meyers that he'd been in trouble with the network for flashing Amy Poehler on the set of Parks and Recreation.

"It's kind of funny now," Pratt said. "They're not going to fire me, I don't think, because we're going to be done this year. Wait, they could fire me! They sent me a letter saying I'm not supposed to make a joke about this. So just so you know, this is really serious. It's going to seem really funny, like I think it's hilarious...When I framed the letter next to the frame of me naked, I was like, 'This is as a reminder.'"

The incident occurred during the second season of the half-hour comedy. "Andy was still dating Ann, or had been dating Ann and was like still in love with Ann, and she wanted him to come to the house," Pratt said, referring to his character and the one played by former cast member Rashida Jones. "He got the signals crossed somehow and thought that she wanted him to come to the house naked and hook up. So I show up naked at the house. Leslie is there—Amy Poehler is there—to receive a naked Andy."

He wore special undies for the scene. "That's what they do in the movies if they're going to pixelate out your junk area," he said. "They don't make you show your junk. They just make it a skin-colored brief."

"I show up at the end of the day andI'm in these skin-colored briefs," Pratt recalled. "I'm not quite eliciting the response that I was hoping to from Amy. She's supposed to say, 'Oh, my gosh! Your penis!'"

After three of four takes, he warned the boom operator he was going to "go snake out" on the next one.

"I went trou-down and the reaction was awesome," Pratt said. "It's the one they used."

Meyers then played the clip, and truth be told, Poehler's reaction is priceless.

What did NBC say about his stunt? "In the letter they did say, like, 'Hey listen, you can't do this, and also, probably don't go joke around about it. It's not a joking matter.' And it's not," the Guardians of the Galaxy star said. "You can't do that because...I don't know," he laughed. "Because you're not supposed to!"